1. Field of the Invention
This invention relates to a process for the production of storable nonionic surfactants with improved resistance to crystallization, in which selected crystallization moderators are added to alk(en)yl oligoglycosides.
2. Statement of Related Art
Alk(en)yl oligoglycosides are important nonionic surfactants which are being used to an increasing extent in laundry detergents, dishwashing detergents and cleaning products by virtue of their favorable detergent properties and their high ecological compatibility.
For this purpose, alk(en)yl oligoglycosides have to be kept available and stored, for example as aqueous solutions or pastes, for certain periods pending final processing. However, since aqueous alk(en)yl oligoglycosides have a pronounced tendency towards crystallization, the homogeneity of such preparations gradually decreases during storage under ambient conditions, resulting in the formation of agglomerates containing water of crystallization which reduce the pumpability of the products to a considerable extent.
Accordingly, alk(en)yl oligoglycosides are not normally stored at room temperature, but at temperatures of at least 40.degree. C. Although the preparations can largely be prevented from crystallizing in this way, storage at elevated temperatures involves additional costs and, moreover, can seriously affect the color quality of the products.
Accordingly, the problem addressed by the present invention was to provide a process by which alk(en)yl oligoglycosides could be stored at temperatures below 40.degree. C. without the pumpability of the products being impaired by the formation of crystalline agglomerates.